1. Field of the Invention
The field of the invention is that of car radios, microcomputers, fax machines, telephones or, again, systems for using up consumption units, for example accounting devices used to count periods of regulated parking. More specifically, the present invention relates to an electronic system with controlled access.
Generally speaking, the invention relates to any electronic system that can be fraudulently misappropriated, and notably to transportable or portable electronic systems. These electronic systems, which are often considerably valuable, are frequently left where they can be seen by potential thieves: for example they are left inside automobiles. This is thus the case with car radios or car telephones which may be a temptation that often causes windows and doors to be broken.
2. Description of the Prior Art
Another electronic system of this type is constituted by accounting devices, used to count periods of regulated parking, that are designed to be placed behind the windscreens of vehicles. A device such as this is described, for example, in the French patent application No. 87/06776 filed on behalf of the SOCIETE INTERNATIONALE POUR L'INNOVATION. These devices, constituted by a pack cooperating with a prepaid electronic ticket, for example a memory card, to decrement fee units memorized in the card as a function of the parking period, are also a focus of interest for potential thieves. This type of device, which can be used to eliminate the need for fixed individual posts (of the pavement parking meter type) or posts used in common by groups of vehicles (of the type installed at the entrances to parking lots), is hired out or sold by municipalities and has a definite value. Since their function entails their being exposed so that they can be seen by officials entrusted with ascertaining, notably, that the parking time has been properly accounted for, they cannot, at least during operation, be removed from the sight of ill-intentioned individuals.
A solution could be envisaged where access to such electronic systems is controlled by making their use conditional on the knowledge of a confidential code, similar to the codes needed to use cash cards or bank credit cards. The numerous data-processing innovations that have been achieved in fields as varied as those of banking, office automation and domestic automation applications have greatly increased the use of codes of this type. Since these codes are confidential and generally ought not to be written on any document carried by the user, it becomes very difficult to memorize them and, above all to make the association between each code and the nature of the operation that it is supposed to authorize. Furthermore, the fact of forgetting a code totally paralyzes the use for which this code is intended, and it generally becomes necessary, notably in banking applications, to have recourse to a complicated procedure in order to obtain knowledge of this code again.
The aim of the present invention is to propose an electronic system with controlled access that is not necessarily linked to the knowledge of a code.
More specifically, an aim of the invention is to provide a system such as this that deprives thieving of any attendant rewards by making this system unusable without the possession of objects that are solely in the hands of the authorized users.
Another aim of the invention is to provide a system such as this wherein the user can decide whether or not it should work in controlled access mode.
A particular object of the invention is to provide a system for using up consumption units, such as an accounting device, with controlled access, for the counting of periods of parking. The invention is particularly promising for this type of device in that it permits its customization. Thus, manufactures of this kind of apparatus can provide packs which, as desired by the user, may or may not be placed in a controlled access mode of operation. A user making use of his prepaid parking pack in a city where thieving is common can customize his device so that none but himself can use it. A user living in a peaceful city where thieving is uncommon can, for his part, choose to keep his device in a free access mode of operation. Should there be a recrudescence of thefts, he will always have the possibility of switching the system over into the controlled access mode of operation. To achieve this, all he needs to do is to acquire a specific card (an access control card), distinct from the cards bearing the consumption units. The first insertion of this card into the device will irreversibly switch the device over into a state of controlled access while at the same time customizing said device since the controlled access card inserted is the obligatory personal key needed to use the device. If necessary, in particular circumstances, provision may be made for a system wherein a competent authority can bring the device back into the free access state by means of a technical manipulation of a specific "master card". However, this arrangement is a vulnerable aspect of the system since, with its becoming possible for the system to return the free access state, such a return could be done fraudulently.